The average person in the U.S. contains detectable levels of more than 100 industrial compounds, pollutants, and chemicals, but predicting the relative risk of this exposure, especially over time, is challenging (US CDC, 2003). Successful development and commercialization of next-generation, low-cost, high-performance technology for predicting compound toxicity would help assess safe levels of environmental exposure-thereby reducing national healthcare costs and producing safer working/living environments. This exposure to environmental toxins plays an important role in aging and oxidation processes, which are key risk factors of macular degeneration, a process that eventually leads to blindness. Importantly, however, there are currently no accepted or practical tests for measuring the retinal toxicity of compounds directly. In vivo assessments of retinal toxicity, when performed, require large numbers of animals, are time-consuming and expensive, and do not provide data on toxicity progression. The ability to prepare stable primary mixed retinal cultures in vitro would allow screening and prioritization of further toxicity testing in a rapid and cost-effective manner. Ideally, such a system should allow differentiation of light-dependent toxicity [phototoxicity] and general toxic effects, and would mimic in vivo toxicity. Therefore, the overall goal of this multi-phase SBIR project is to develop, validate, and commercialize Ocuscreen(tm), Acucela's proprietary retinal culture screening system, as a next-generation in vitro system for ranking the relative (photo)toxicity of environmental toxins, and to have this assay incorporated as a part of the regulatory framework for the commercialization of chemicals. The Specific Aims for Phase I of this project are to identify a group of known retinal toxicants, to prove the feasibility of ranking their (photo)toxic potential, and finally to show these rankings correlate with in vivo literature data. Demonstrating that we can predict (photo)toxicity (or lack thereof) in a small class of representative compounds will establish the predictive potential of our new system within the limited scope of the Phase I proof-of-concept project, and will set the stage for a larger Phase II demonstration effort. Phase I will also provide sufficient data for Ocuscreen to be nominated as an alternative test method to the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM), and will allow us to determine how well Ocuscreen meets ICCVAM performance standards. Phase II work will involve establishing a large photoreceptor toxicity database of chemicals-built both from existing knowledge and results from our assay system-to improve the predictive accuracy of compound safety. Phase III of the project will be focused on establishing a commercial screening service for photoreceptor toxicity. Even without formal regulatory adoption, the ability to accurately predict toxic potential will provide a compelling service to chemical companies and will represent an important step in protecting human health. The average person in the U.S. contains detectable levels of more than 100 industrial compounds, pollutants, and chemicals, but predicting the risk of this exposure, especially to eye toxicity, is challenging. Current prediction methods require large numbers of animals, are time-consuming and expensive, and do not provide data on toxicity progression. The overall goal of this project is to develop, validate, and commercialize Acucela's proprietary retinal culture screening system as a next-generation, practical in vitro system for evaluating the health effects of environmental toxicants. [unreadable] [unreadable] [unreadable]